<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <style>
      #canvas {
          background: #f1f1f1;
      }
  </style>
</head>
<body>
<canvas id="canvas" width="300" height="300"></canvas>
<script>
    window.onload = () => {
        const canvas = document.getElementById('canvas')
        const ctx = canvas.getContext('2d')
        // 绘制矩形
        const drawRect = () => {

        }
        // drawRect()

    }

</script>
</body>
</html>
